The project seeks to understand the clinical and molecular basis of the Lenz microphthalmia syndrome. This disorder comprises anophthalmia or microphthalmia (small or absent eyes with blindness), mental retardation, and skeletal anomalies. We have identified a large family affected by this disorder and have mapped the gene to the short arm of the X chromosome. This result is surprising because another family with this disorder maps to the long arm of the X chromosome. This means that Lenz microphthalmia is probably an amalgam of two disorders. We are using positional cloning to isolate the gene that is altered in the condition. We have identified a candidate gene that is altered in four families with Lenz syndrome and another related condition, the Oculo-facio-cardi-dental syndrome. We are currently assessing the functional consequence of these mutations.